Fish are expected to shrink in size by 20 to 30 per cent if ocean temperatures continue to climb due to climate change, a study has warned.
The study by researchers at the University of British Columbia in Canada provides a deeper explanation of why fish are expected to decline in size.
“Fish, as cold-blooded animals, cannot regulate their own body temperatures. When their waters get warmer, their metabolism accelerates and they need more oxygen to sustain their body functions,” said William Cheung, associate professor at the Institute for the Ocean and Fisheries.
“There is a point where the gills cannot supply enough oxygen for a larger body, so the fish just stops growing larger,” said Cheung. According to Daniel Pauly, the study’s lead author, as fish grow into adulthood their demand for oxygen increases because their body mass becomes larger.
However, the surface area of the gills — where oxygen is obtained — does not grow at the same pace as the rest of the body. He describes this set of principles that explains why fish are expected to shrink “gill-oxygen limitation theory.”